Access for mobile devices to packet-based networks such as the Internet across radio telecommunications networks is an important growth area for the telecommunications industry. It is known, for example from 3GPP TS (Technical Standard) 23.401, to provide a system whereby a mobile device connects to a packet-based network such as the Internet by means of a serving gateway and a PDN (public data network) gateway (referred to herein as a home gateway).
As the mobile device is moved through the radio telecommunications network, connections to different serving gateways will be made between the mobile device dependent upon its geographical location. However, as the serving gateways hand over the connection between the mobile device and the packed-based network between one another, they use the same home gateway for the connection.
This allows the home gateway to keep the mobile device connected to the packet-based network using the same connection. A mobile device can therefore “roam” throughout the radio telecommunications network and keep the same network connection, even though it may have to rely on the services of different serving gateways. The home gateway tunnels packets for the connection between the packet-based network and the mobile device and sends them to the appropriate serving gateway.
However, problems arise should the home or serving gateway fail, or should the connection between the serving gateway and its support node—the node which control the connections made by the serving gateway—fail. A single gateway may support many connections. Once a serving gateway support node detects the failure, it considers all of the connections to that gateway invalid and in effect forces the mobile devices to re-establish a connection, thus disconnecting each user from the packet based network. Given the number of connections that a gateway may support, this can overload the network with connection establishment requests.